Radiation Oncology

Brachytherapy

Copyright 2008, Mayo Foundation for Medical Education and Research

Brachytherapy is a procedure where small metal implants (usually about the size of a piece of rice) are put inside the body in or near a cancerous tumor. Inside the small implant is some radioactive material. The radioactive material is sealed inside the implant and cannot get out. The implant stays in the location where it was positioned and exposes the tumor to a constant stream of radiation until the radioactivity decays away. Sometimes the implants are temporary—the implant is inside the body only for a short period of time (24-48 hours, while the patient is hospitalized) and is then removed—or it can be permanently placed in the tumor and it is safe for the patient to go home.

Linear Accelerators

Copyright 2008, Mayo Foundation for Medical Education and Research

A linear accelerator (also called a LINAC) is a very large device that emits high-energy x rays and electron beams. It is the most common device used in radiation oncology for cancer treatment. The linear accelerator x-ray or electron beam can be highly collimated so the energy is delivered to the tumor while sparing normal tissues. A specialized type of treatment that is becoming more common with linear accelerators is called intensity modulated radiation therapy (IMRT). The intent of IMRT is to do a better job of delivering the beam to diseased tissue without harming surrounding tissues.

Gamma Stereotactic Radiosurgery

Copyright 2008, Mayo Foundation for Medical Education and Research

A gamma stereotactic radiosurgery unit (sometimes called a gamma knife) is a highly specialized piece of equipment. Very high doses of radiation are delivered to very small diseased areas within the head and neck. These units are typically used to treat or reduce the effects of tumors, blood vessel defects, motor issues (like face tics), epilepsy, and Parkinson’s disease.